{"id":561229,"date":"2026-06-30T08:05:10","date_gmt":"2026-06-30T08:05:10","guid":{"rendered":"https:\/\/www.europesays.com\/ie\/561229\/"},"modified":"2026-06-30T08:05:10","modified_gmt":"2026-06-30T08:05:10","slug":"the-ozone-holes-earliest-cause-wasnt-cfcs-after-all","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/ie\/561229\/","title":{"rendered":"The Ozone Hole’s Earliest Cause Wasn’t CFCs After All"},"content":{"rendered":"

When researchers first discovered the Antarctic ozone hole<\/a> in 1985, it was a shock to the scientific community. The wave of studies that followed suggested it began forming<\/a> in the 1970s, driven primarily by chlorofluorocarbons<\/a> (CFCs). Now, a new study offers a totally different perspective on its origin.<\/p>\n

The findings, published<\/a> today in the journal Proceedings of the National Academy of Sciences, suggest that the first signs of ozone depletion actually appeared as early as 1957. Though it took another 30 years for scientists to develop the atmospheric monitoring capabilities that led them to discover the hole, the ozone layer began thinning decades earlier.<\/p>\n

The surprises don\u2019t stop there. The researchers determined that the first signal of ozone loss appeared not in the Antarctic, but in the upper stratosphere of the tropics. What\u2019s more, the early stages of depletion were not driven by CFCs but by carbon tetrachloride, another industrial chemical used as a dry-cleaning and degreasing agent in the 1930s.<\/p>\n

\u201cThe fact that ozone depletion would have happened as early as the late 1950s, which is much earlier than I would have thought, just absolutely blew my mind,\u201d lead author Susan Solomon, the Lee and Geraldine Martin Professor of Environmental Studies and Chemistry at the Massachusetts Institute of Technology, said<\/a> in a statement. Solomon was an early pioneer in the study of ozone\u2019s effects on the atmosphere and the first to show that CFCs were primarily responsible for eroding Antarctic ozone, according to MIT.<\/p>\n

\u201cIt turns out there was another compound that caused ozone depletion much earlier than CFCs,\u201d she said. \u201cThis was a big surprise.\u201d<\/p>\n

Rewriting the ozone hole\u2019s history <\/p>\n

The ozone layer sits<\/a> in the stratosphere between 7 and 31 miles (11 and 50 kilometers) above Earth\u2019s surface. It serves as the planet\u2019s natural sunscreen, blocking out most of the Sun\u2019s harmful ultraviolet (UV) radiation and protecting life down below.<\/p>\n

In the late 1970s, British Antarctic Survey researcher Jonathan Shanklin noticed<\/a> something strange while analyzing data from the Dobson ozone spectrophotometer at Halley Research Station. This instrument measures the amount of UV radiation reaching Earth to infer how much ozone is in the atmosphere. Since the late 1970s, there had been a systematic decline in the amount of spring ozone over Antarctica. By 1984, the ozone layer over Halley was only two-thirds as thick as it had been in earlier decades.<\/p>\n

Shanklin and colleagues published<\/a> their findings in 1985, marking the discovery of the ozone hole. To be clear, it isn\u2019t technically a \u201chole\u201d where ozone is never present. Rather, it\u2019s a region of exceptionally depleted stratospheric ozone that forms<\/a> over Antarctica at the beginning of Southern Hemisphere spring (August through October).<\/p>\n

In the mid-1970s, researchers suggested<\/a> that CFCs could deplete the ozone layer, but there was no direct evidence that this was actually taking place. After Shanklin discovered the ozone hole, Solomon led Antarctic expeditions to measure the stratosphere\u2019s composition, ultimately confirming that CFC pollution was the primary driver of ozone depletion.<\/p>\n

Since then, global efforts to reduce CFC emissions have led<\/a> to significant recovery, but Solomon\u2019s latest research suggests a different chemical was eating away at the ozone layer long before the ozone hole was discovered.<\/p>\n

The first chemical culprit <\/p>\n

Solomon and her colleagues carried out a thought experiment in which they imagined a world where today\u2019s atmospheric monitoring capabilities were available in 1950. Under this scenario, they used modeling to simulate atmospheric chemistry over the past 76 years, finding that the earliest sign of ozone depletion would have been detectable over the tropics by 1957.<\/p>\n

The only chemical pollutant that could explain this is carbon tetrachloride. \u201cThat\u2019s the only ozone-depleting substance that was increasing that early,\u201d Solomon said. \u201cWe started using carbon tetrachloride in the 1930s as a dry-cleaning agent, and as a degreasing solvent. We didn\u2019t start using CFCs until quite a bit later.\u201d<\/p>\n

Fortunately for the ozone layer, carbon tetrachloride use was banned<\/a> from consumer products in the 1970s due to health concerns, then further restricted<\/a> by the Montreal Protocol in 1990. Still,\u00a0Solomon believes this finding underscores the importance of long-term atmospheric monitoring so that we can fully understand how it responds to chemical pollution.<\/p>\n

\u201cWe\u2019ve gone through a big effort to get rid of these chemicals,\u201d she said. \u201cDon\u2019t we have an obligation to keep monitoring to make sure the atmosphere responds the way we think it should?\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"When researchers first discovered the Antarctic ozone hole in 1985, it was a shock to the scientific community.…\n","protected":false},"author":2,"featured_media":561230,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_share_on_mastodon":"0"},"categories":[269],"tags":[39611,12048,9132,18,440,19,17,133],"class_list":["post-561229","post","type-post","status-publish","format-standard","has-post-thumbnail","category-environment","tag-air-pollution","tag-antarctica","tag-atmospheric-science","tag-eire","tag-environment","tag-ie","tag-ireland","tag-science"],"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@ie\/116838027836195658","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/561229","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=561229"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/561229\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/561230"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=561229"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=561229"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=561229"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}